Shelter · Weather Readiness
Air sealing, insulation, windows, doors, and drainage. Each improvement reduces energy costs in normal conditions and extends how long a home stays warm, cool, and dry when utility service is interrupted.
Start with air sealingThe logic of weatherproofing
The Department of Energy estimates that air leakage accounts for 25 to 40 percent of heating and cooling energy in a typical American home.[1] Sealing those leaks reduces energy costs year-round. It also means the home loses heat more slowly during a winter outage and stays cooler longer during a summer outage.
A well-insulated, tightly sealed home that loses only one or two degrees per hour during a cold snap stays livable for two or three days without heat. A poorly insulated home that loses five degrees per hour becomes dangerous in under 12 hours. The weatherproofing done to save money in February is the same work that determines whether the household stays home or seeks shelter during a power failure.
This guide covers the home envelope: the walls, windows, doors, and foundation that separate indoor conditions from outdoor ones. It does not cover HVAC equipment or backup heating and cooling systems, which are addressed in the Energy section.
Highest return first
Air sealing is the single highest-return weatherproofing action for most homes. The materials are inexpensive. The work is accessible. The impact is immediate.
Paintable latex caulk
For gaps around window frames, door frames, and trim. Applies easily, paints over, and lasts 5 to 10 years. Cost: under $5 per tube. One tube covers a typical window.
Expanding foam sealant
For larger gaps around pipes, wires, and ducts. Use minimal-expanding foam around windows to avoid bowing the frame. Cost: $5 to $10 per can.
Self-adhesive weatherstripping
For the contact surfaces of door and window frames. Replace when compressed flat. V-strip weatherstripping lasts longer than foam tape. Cost: $10 to $25 per door.
Door sweep or draft seal
For the gap at the base of exterior doors. Screw-mounted sweeps last longer than adhesive versions. Cost: $10 to $30 per door.
Free energy audit. Many utility companies offer free or low-cost home energy audits that include a blower-door test, which pressurizes the home and measures total air leakage. The auditor identifies every major leak location and often provides rebates on sealing materials or contractor work. Check your utility company's website under "energy efficiency programs."
Windows and doors
Windows and doors account for a significant portion of home heat loss. The improvements below are organized from least expensive and renter-accessible to most expensive and homeowner-specific.
Insulated or blackout curtains reduce heat transfer through windows by 10 to 25 percent. Keep them open during sunny winter days to gain solar heat. Close them at night and on overcast days to retain it. Close them on south and west-facing windows during summer afternoons. Cost: $20 to $80 per window.
Renter-friendly: yes
Shrink-film window insulation kits add a temporary second pane effect to single-pane windows. Applied with double-sided tape and a hair dryer, removed in spring. Low-e window film applied directly to the glass reduces heat gain in summer without the same winter benefit. Cost: $5 to $15 per window for shrink film.
Renter-friendly: yes (seasonal)
Check that exterior doors are solid core and that they close flush against the frame on all four sides. A hollow-core exterior door provides almost no insulation. A gap you can see light through at the door frame means significant air and heat loss. Replace weatherstripping on any door where you can feel drafts. A screw-mounted door sweep on the base costs $15 to $25 and makes a measurable difference.
Renter-friendly: weatherstripping yes; door replacement is a landlord task
Replacing single-pane windows with double or triple-pane low-e units is a significant improvement but takes years to pay back through energy savings alone. The case is stronger when combined with comfort improvement and noise reduction, or when a window is failing (fogged between panes, broken seals, difficulty operating). Prioritize by window size and orientation: large north-facing windows gain no solar benefit and lose the most heat.
Cost: $300 to $800+ per window installed. Tax credits may apply.
Drainage
Foundation water intrusion is one of the most common and expensive home damage sources. Most of it is caused by drainage problems that direct water toward the house rather than away from it.
Clean gutters in spring and fall. A clogged gutter overflows directly against the foundation. Downspouts should discharge at least four feet from the foundation. Add an extension or splash block if they terminate close to the house. Flexible drain pipe extensions that discharge further out are available for under $20.
Ice dams form when heat from the house melts snow on the roof and the meltwater refreezes at the cold overhang. Clogged gutters worsen this. Good attic insulation that keeps the roof uniformly cold is the long-term fix. In the short term, a roof rake removes snow before it melts.
The ground around the foundation should slope away from the house at roughly one inch per foot for the first six feet. Over time, soil settles and this slope can reverse, directing water toward the foundation. Adding topsoil or compost to build up the grade away from the house is inexpensive and effective. Avoid planting shrubs or mulching directly against the foundation, which holds moisture.
Hairline cracks in concrete block or poured concrete foundation walls allow water intrusion under hydrostatic pressure. Hydraulic cement and crystalline waterproofing compounds applied from the interior seal active leaks. Larger cracks or chronic water problems warrant a professional evaluation. A vapor barrier on a crawlspace floor prevents ground moisture from entering the home and causing rot and mold in the structure above.
A sump pump in a basement that collects groundwater is the drainage system of last resort. If you have a sump pump, test it annually and consider a battery backup for the motor so it continues working during the power outages that often accompany the heavy rain events that stress it most.
Common mistakes
01
Air sealing and insulation work together. Adding insulation without sealing the gaps around it reduces its effectiveness because air still moves through the leaks. Do both in the same project, starting with sealing.
02
Standard expanding foam expands significantly as it cures. Used around window and door frames, it can bow the frame and prevent the window or door from operating correctly. Use minimal-expanding or "window and door" foam in those locations.
03
A well-sealed home needs controlled ventilation to maintain air quality. If a home is significantly tightened, mechanical ventilation (a heat recovery ventilator or energy recovery ventilator) may be needed to exchange stale indoor air for fresh outdoor air without losing all the heating or cooling benefit of sealing.
04
A wet basement wall sealed from the inside often pushes water to find another entry point. Identify whether the water is coming through the wall under hydrostatic pressure, down the wall from above, or up from below. The solution differs in each case. Sealing from the inside is appropriate for some situations and counterproductive for others.
Continue
More weather readiness
High winds, flooding, winter preparation, extreme heat, and seasonal maintenance. Back to the full category.
All weather guidesThe energy side
A weatherproofed home stays warm longer. These guides cover the backup heating options that work inside a tighter home.
Heating during outages